First sandwich loaf! Done on the outside but not inside?

I’m new to bread baking and followed this recipe. The crumb is a little too dense maybe? It tastes gummy. Should I have baked it longer? I baked for 30 min and was ready to stop as the top was golden brown and the bottom sounded hollow when thumped. But the internal temperature was ~170 F so I put it back for 5 more minutes and this time the internal temp was 180 F. The recipe said it should be 190 F but I was worried about drying it out. I used the King Arthur recipe : https://www.kingarthurbaking.com/recipes/classic-sandwich-bread-recipe